DESCRIPTION (Adapted from the applicant's description): The explosive nature of the South African epidemic calls for urgent measures for HIV prevention in the country. The multidisciplinary group of researchers from two National (Johannesburg and Durban) and two International sites (UK and USA) propose a series of innovative studies of determining acceptability of microbicides. The extensive experience of the applicants in conducting clinical, behavioral, pharmaceutical, social, biostatistics, epidemiological and health systems research places them in a unique position to conduct a wide range of studies to assess acceptability. The research objectives will be addressed in five phases with a combination of qualitative and quantitative methods. Objectives include: 1. Retrospective assessment of factors associated with continued use of a vaginal microbicide among sex workers who had participated in a Phase III trial; 2. Development of a standardized tool for measuring acceptability; 3. Prospective assessment of factors associated with continued use of a vaginal microbicide in a non-clinical setting (if appropriate products are available); 4. Ascertainment of acceptable product characteristics and delivery mechanisms for microbicides using inert products and application of these findings to assessing the acceptability of several products currently in development; and 5. Identification of facilitators and barriers to the introduction and use of microbicides among health care providers and potential users in South Africa.